Strong recovery of dragonflies in recent decades in The Netherlands
Termaat, T. ; Grunsven, R.H.A. van; Plate, C.L. ; Strien, A. van - \ 2015
Freshwater Science 34 (2015)3. - ISSN 2161-9549 - p. 1094 - 1104.
change odonata corduliidae - boreal forest lakes - climate-change - trends - conservation - assemblages - indicators - integrity - abundance - plants
Many dragonfly species in The Netherlands declined in the 20th century because of acidification, eutrophication, and desiccation of lotic and lentic habitats and canalization of streams and rivers. These pressures peaked in the 1970s, when 26 of 65 native species had an unfavorable conservation status on the 1997 Dutch Red List. Since the 1980s, environmental regulations have led to improved water quality, and any habitat restoration projects have been carried out. We used standardized monitoring data (1999–2013) and unstandardized observations (1991–2013) to investigate how dragonflies have changed in the last 20 y on a national scale. We compared trends of dragonfly species from different habitat types and with southern vs northern distribution in Europe. Dragonflies recovered strongly in The Netherlands in a period of ~20 y, probably because of recent habitat improvements. Lotic species have benefitted more than lentic species, and southern species have more positive trends than northern species, suggesting that climate change has contributed to the recovery. Dragonflies were resilient and able to quickly recover when their habitats were restored. Recovery has led to a better conservation status for many species. Unstandardized data delivered results consistent with those from monitoring data and had greater statistical power to detect trends because many more unstandardized data than standardized data were available. Thus, when the goal is to provide a general overview of changes in dragonflies, unstandardized data can outperform standardized abundance data. However, abundance data may deliver complementary information for individual species. Our results support the suitability of dragonflies as indicators of freshwater habitat condition, but they recover more strongly in The Netherlands than many other insects, possibly because of their higher dispersal abilities or different habitat requirements.
Offshore wind park monitoring programmes, lessons learned and recommendations for the future
Lindeboom, H.J. ; Degraer, S. ; Dannheim, J. ; Gill, A.B. ; Wilhelmsson, D. - \ 2015
Hydrobiologia 756 (2015)1. - ISSN 0018-8158 - p. 169 - 180.
renewable energy development - north-sea - communities - impacts - benthos - farms - power - biodiversity - assemblages - management
Over a decade of monitoring offshore wind park environmental impact triggered a reflection on the overall objectives and how to best continue with the monitoring programmes. Essentially, basic monitoring has to be rationalised at the level of the likelihood of impact detection, the meaningfulness of impact size and representativeness of the findings. Targeted monitoring is crucial and should continue to be applied to disentangle processes behind observed impacts, for instance the overarching artificial reef effect caused by wind parks. The major challenge, however, remains to achieve a reliable assessment of the cumulative impacts. A continuous international consultation and collaboration with marine scientists, managers, government officials and industry will be needed to ensure an optimisation of the future monitoring programmes.
Macroinvertebrate survival during cessation of flow and streambed drying in a lowland stream
Verdonschot, R.C.M. ; Oosten-Siedlecka, A.M. van; Braak, C.J.F. ter; Verdonschot, P.F.M. - \ 2015
Freshwater Biology 60 (2015)2. - ISSN 0046-5070 - p. 282 - 296.
invertebrate communities - prairie stream - desert stream - drought - intermittent - assemblages - responses - rivers - recolonization - resilience
1.The number of perennial low-order lowland streams likely to experience intermittent flow is predicted to increase in north-western Europe. To understand the effects of such a change on macroinvertebrates, a field experiment was carried out in a currently perennial sandy lowland stream. 2.Using a before–after control–impact design, the flow regime was manipulated to yield two distinct treatments: stagnation (although with little water loss) and drying of the stream (although artificial remnant pools remained in the bed). There was also an unmanipulated control reach. The two treatments were applied simultaneously in separate, consecutive reaches, resulting in 29 days of stagnation and 25 days of streambed drying with surface water only present in the remnant pools. Changes in macroinvertebrate richness, abundance and community composition were recorded, and we assessed whether these changes could be explained by ecological preferences for flow of the various taxa. 3.Stagnation resulted in only minor changes in community composition. A small number of rheophilic taxa disappeared, while taxa preferring standing waters complemented those already present, increasing total biodiversity. In remnant pools in the otherwise dry reach, richness and abundance peaked after they became isolated, indicating a concentration of invertebrates. A subsequent steep decline in richness coincided with hypoxia and increasing conductivity. Culex pipiens/torrentium colonised the pools and was then dominant. Only a small subset of the assemblage successfully used the dry streambed as a refuge. 4.The effect of a shift from perennial to intermittent flow evidently depends on the degree of habitat change. Environmental conditions after cessation of flow are crucial in determining lowland stream macroinvertebrate persistence during water drawdown.
How to assess species richness along single environmental gradients? Implications of potential versus realized species distributions
Goethem, T.M.W.J. van; Huijbregts, M.A.J. ; Wamelink, G.W.W. ; Schipper, A.M. - \ 2015
Environmental Pollution 200 (2015). - ISSN 0269-7491 - p. 120 - 125.
sensitivity distributions - field data - plant - diversity - abundance - macroinvertebrates - acidification - consequences - biodiversity - assemblages
Quantifying relationships between species richness and single environmental factors is challenging as species richness typically depends on multiple environmental factors. Recently, various methods have been proposed to tackle this challenge. Using a dataset comprising field observations of grassland vegetation and measured pH values, we compared three methods for deriving species richness response curves. One of the methods estimates species richness close to the maximum species richness observed at the sites, whereas the other two provide estimates of the potential species richness along the environmental gradient. Our response curves suggest that potential species richness of grasslands is slightly more sensitive to acidification than realized plant species richness. However, differences in corresponding environmental quality standards (EQS) for acidification were small compared to intrinsic spatial differences in natural soil pH, indicating that natural background values are more important to consider in the derivation of EQS for pH than methodological differences between the three approaches.
Soil biodiversity and DNA barcodes: opportunities and challenges
Orgiazzi, A. ; Bonnet Dunbar, M. ; Panagos, P. ; Groot, G.A. de; Lemanceau, P. - \ 2015
Soil Biology and Biochemistry 80 (2015)1. - ISSN 0038-0717 - p. 244 - 250.
molecular microbial ecology - bacterial communities - ecosystem services - diversity - fungal - patterns - identification - assemblages - resilience - extraction
Soils encompass a huge diversity of organisms which mostly remains to be characterized due to a number of methodological and logistical issues. Nonetheless, remarkable progress has been made in recent years toward developing strategies to characterize and describe soil biodiversity, especially thanks to the development of molecular approaches relying on direct DNA extraction from the soil matrix.Metabarcoding can be applied to DNA from any environment or organism, and is gaining increasing prominence in biodiversity studies. This approach is already commonly used to characterize soil microbial communities and its application is now being extended to other soil organisms, i.e. meso- and macro-fauna.These developments offer unprecedented scientific and operational opportunities in order to better understand soil biodiversity distribution and dynamics, and to propose tools and strategies for biodiversity diagnosis. However, these opportunities also come with challenges that the scientific community must face. Such challenges are related to i) clarification of terminology, (ii) standardisation of methods and further methodological development for additional taxonomic groups, (iii) development of a common database, and (iv) ways to avoid waste of information and data derived from metabarcoding. In order to facilitate common application of metabarcoding in soil biodiversity assessment, we discuss these opportunities and challenges and propose solutions towards a more homogeneous framework.
NINJA: An automated calculation system for nematode-based biological monitoring
Sieriebriennikov, B. ; Ferris, H. ; Goede, R.G.M. de - \ 2014
European Journal of Soil Biology 61 (2014). - ISSN 1164-5563 - p. 90 - 93.
soil food-web - maturity index - communities - assemblages
Monitoring of soil quality and health provides critical insights into the performance of ecosystems. Nematodes are useful indicators of soil condition because they are ubiquitous, represent different trophic levels of a soil food web and are convenient to work with. Several quantitative analyses of nematode assemblages have been developed and used in monitoring programs and by individual researchers. However, the calculations of the metrics involved are quite complicated. Since they are done manually using spreadsheet software, the calculations are time-consuming and error-prone and usually involve a significant learning curve for the user. We have developed an R code to perform these calculations. The code is compiled in html and deployed over the web. It is and will remain freely accessible and has a user-friendly interface. It requires only an input table with taxonomic inventory data and provides output within a few seconds.
Combining multi-dimensional scaling and cluster analysis to describe the diversity of rural households
Pacini, G.C. ; Colucci, D. ; Baudron, F. ; Righi, E. ; Corbeels, M. ; Tittonell, P.A. ; Stefanini, F.M. - \ 2014
Experimental Agriculture 50 (2014)3. - ISSN 0014-4797 - p. 376 - 397.
farms - management - heterogeneity - assemblages - typologies - indicators - region - spain
Capturing agricultural heterogeneity through the analysis of farm typologies is key with regard to the design of sustainable policies and to the adoptability of new technologies. An optimal balance needs to be found between, on the one hand, the requirement to consider local stakeholder and expert knowledge for typology identification, and on the other hand, the need to identify typologies that transcend the local boundaries of single studies and can be used for comparisons. In this paper, we propose a method that supports expert-driven identification of farm typologies, while at the same time keeping the characteristics of objectivity and reproducibility of statistical tools. The method uses a range of multivariate analysis techniques and it is based on a protocol that favours the use of stakeholder and expert knowledge in the process of typology identification by means of visualization of farm groups and relevant statistics. Results of two studies in Zimbabwe and Kenya are shown. Findings obtained with the method proposed are contrasted with those obtained through a parametric method based on latent class analysis. The method is compared to alternative approaches with regard to stakeholder-orientation and statistical reliability.
Impact on demersal fish of a large-scale and deep sand extraction site with ecosystem-based landscaped sandbars
Jong, M.F. de; Baptist, M.J. ; Hal, R. van; Boois, I.J. de; Lindeboom, H.J. ; Hoekstra, P. - \ 2014
Estuarine Coastal and Shelf Science 146 (2014). - ISSN 0272-7714 - p. 83 - 94.
southern north-sea - pleuronectes-platessa - limanda-limanda - marine sand - plaice - invertebrates - assemblages - environment - responses - habitats
For the seaward harbour extension of the Port of Rotterdam in the Netherlands, approximately 220 million m3 sand was extracted between 2009 and 2013. In order to decrease the surface area of direct impact, the authorities permitted deep sand extraction, down to 20 m below the seabed. Biological and physical impacts of large-scale and deep sand extraction are still being investigated and largely unknown. For this reason, we investigated the colonization of demersal fish in a deep sand extraction site. Significant differences in demersal fish species assemblages in the sand extraction site were associated with variables such as water depth, median grain size, fraction of very fine sand, biomass of white furrow shell (Abra alba) and time after the cessation of sand extraction. Large quantities of undigested crushed white furrow shell fragments were found in all stomachs and intestines of plaice (Pleuronectes platessa), indicating that it is an important prey item. One and two years after cessation, a significant 20-fold increase in demersal fish biomass was observed in deep parts of the extraction site. In the troughs of a landscaped sandbar however, a significant drop in biomass down to reference levels and a significant change in species assemblage was observed two years after cessation. The fish assemblage at the crests of the sandbars differed significantly from the troughs with tub gurnard (Chelidonichthys lucerna) being a Dufrêne-Legendre indicator species of the crests. This is a first indication of the applicability of landscaping techniques to induce heterogeneity of the seabed although it remains difficult to draw a strong conclusion due the lack of replication in the experiment. A new ecological equilibrium is not reached after 2 years since biotic and abiotic variables are still adapting. To understand the final impact of deep and large-scale sand extraction on demersal fish, we recommend monitoring for a longer period, at least for a period of six years or even longer. Keywords infauna; epifauna; sediment; ground fish; sand mining; North Sea
Assessing the impacts of livestock production on biodiversity in rangeland ecosystems
Alkemade, R. ; Reid, R.S. ; Berg, M. van den; Leeuw, J. de; Jeuken, M. - \ 2013
Proceedings of the National Academy of Sciences of the United States of America 110 (2013)52. - ISSN 0027-8424 - p. 20900 - 20905.
land-use changes - south-africa - diversity - conservation - assemblages - grassland - management - scenarios - responses - savanna
Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge about livestock grazing impacts on biodiversity, expressed in mean species abundance (MSA) of the original rangeland native species assemblages, through metaanalysis of peer-reviewed literature. MSA values, ranging from 1 in natural rangelands to 0.3 in man-made grasslands, were entered in the IMAGE-GLOBIO model. This model was used to assess the impact of change in food demand and livestock production on future rangeland biodiversity. The model revealed remarkable regional variation in impact on rangeland area and MSA between two agricultural production scenarios. The area of used rangelands slightly increases globally between 2000 and 2050 in the baseline scenario and reduces under a scenario of enhanced uptake of resource-efficient production technologies increasing production [high levels of agricultural knowledge, science, and technology (high-AKST)], particularly in Africa. Both scenarios suggest a global decrease in MSA for rangelands until 2050. The contribution of livestock grazing to MSA loss is, however, expected to diminish after 2030, in particular in Africa under the high-AKST scenario. Policies fostering agricultural intensification can reduce the overall pressure on rangeland biodiversity, but additional measures, addressing factors such as climate change and infrastructural development, are necessary to totally halt biodiversity loss.
Habitat functionality for the ecosystem service of pest control: reproduction and feeding sites of pests and natural enemies
Bianchi, F.J.J.A. ; Schellhorn, N.A. ; Cunningham, S.A. - \ 2013
Agricultural and Forest Entomology 15 (2013)1. - ISSN 1461-9555 - p. 12 - 23.
agricultural landscapes - coccinellidae - agroecosystems - biodiversity - assemblages - coleoptera - density - aphids - sinks
1 Landscape management for enhanced natural pest control requires knowledge of the ecological function of the habitats present in the landscape mosaic. However, little is known about which habitat types in agricultural landscapes function as reproduction habitats for arthropod pests and predators during different times of the year. 2 We studied the arthropod assemblage on six crops and on the seven most abundant native plant species in two landscapes over 1 year in Australia. Densities of immature and adult stages of pests and their predators were assessed using beat sheet sampling. 3 The native plants supported a significantly different arthropod assemblage than crops. Native plants had higher predator densities than crops over the course of the year, whereas crops supported higher pest densities than the native plants in two out of four seasonal sampling periods. Crops had higher densities of immature stages of pests than native plants in three of four seasonal sampling periods, implying that crops are more strongly associated with pest reproduction than native plants. Densities of immature predators, excluding spiders, were not different between native plants and crops. Spiders were, however, generally abundant and densities were higher on native plants than on crops but, because some species disperse when immature, there is less certainty in identifying their reproduction habitat. 4 Because the predator to pest ratio on native plant species showed little variation, and spatial variation in arthropod assemblages was limited, the predator support function of native vegetation may be a general phenomenon. Incentives that maintain and restore native remnant vegetation can increase the predator to pest ratio at the landscape scale, which could enhance pest suppression in crops.
Sponge species composition, abundance, and cover in marine lakes and coastal mangroves in Berau, Indonesia
Becking, L.E. ; Cleary, D.F.R. ; Voogd, N.J. de - \ 2013
Marine Ecology Progress Series 481 (2013). - ISSN 0171-8630 - p. 105 - 120.
spermonde archipelago - neighbor matrices - east kalimantan - kakaban-island - beta diversity - porifera - assemblages - variability - variables - scale
We compared the species composition, abundance, and cover of sponges in 2 marine lakes (Kakaban Lake and Haji Buang Lake) and adjacent coastal mangroves on the islands of Kakaban and Maratua in the Berau region of Indonesia. We recorded a total of 115 sponge species, 33 of which were restricted to Kakaban Lake, 18 to Haji Buang Lake, and 30 to coastal mangroves on Maratua Island. Only 13 species were shared among all habitats. The 2 marine lakes are located 10 km apart, but their assemblages were more similar to each other than to the bay mangrove systems just 200 to 500 m away. Our results show that marine lakes represent a distinct habitat with significantly higher sponge cover and abundance as well as a markedly different species composition when compared with coastal mangroves. In both lake and coastal mangrove habitats there was a pronounced gradient in composition away from the shore with the primary difference between solid (root or rock) and soft substrate (mud or sand). Each substrate type harbored different sets of species in both lake and coastal mangrove habitats. There was no significant difference in sponge species composition, abundance, or cover between semi-permanent transects sampled in 2008 and 2009. We show for the first time that mangroves in the Indo-Pacific harbor a diverse array of sponge species and, further, that marine lakes harbor numerous unique species hitherto unknown to science.
Avian response to tidal freshwater habitat creation by controlled reduced tide system
Beauchard, O. ; Jacobs, S. ; Ysebaert, T. ; Meire, P. - \ 2013
Estuarine Coastal and Shelf Science 131 (2013). - ISSN 0272-7714 - p. 12 - 23.
bird species-diversity - ecological restoration - benthic invertebrates - managed realignment - estuary - marsh - communities - shorebirds - colonization - assemblages
Human activities have caused extensive loss of estuarine wetlands, and the restoration of functional habitats remains a challenging task given several physical constraints in strongly embanked estuaries. In the Schelde estuary (Belgium), a new tidal marsh restoration technique, Controlled Reduced Tide system (CRT), is being implemented in the freshwater zone. A polder area of 8.2 ha was equipped with a CRT to test the system functionality. Among different ecological compartments that are studied for assessing the CRT restoration success, avifauna was monitored over three years. The tidal regime generated a habitat gradient typical of tidal freshwater wetlands along which the distributions of bird and ecological groups were studied. 103 bird species were recorded over the three years. In addition to many generalist bird species, several specialist species typical of the North Sea coast were present. Thirty-nine species of local and/or international conservation interest were encountered, emphasising the importance of this habitat for certain species. Species communities and ecological groups were strongly habitat specific and non-randomly organized across habitats. Spatiotemporal analyses highlighted a rapid habitat colonization, and a subsequent stable habitat community structure across seasons in spite of strong seasonal species turnovers. Hence, these findings advocate CRT implementation as a means to effectively compensate for wetland habitat loss.
Successful overwintering of arthropods in roadside verges
Schaffers, A.P. ; Raemakers, I.P. ; Sykora, K.V. - \ 2012
Journal of Insect Conservation 16 (2012)4. - ISSN 1366-638X - p. 511 - 522.
species composition - beetles coleoptera - conservation value - carabid beetles - abundance - assemblages - hymenoptera - dispersal - corridors - diversity
In densely populated areas, roadside verges often provide the last semi-natural habitats available. Their ecological value is often stressed by bio survey results. Yet insect summer surveys potentially misjudge the value of a biotope (roadside or otherwise) since the occurrences of species may only be seasonal, or even transient. To effectively ascertain the importance of a site for insects, species must be shown to complete their life cycle there or at least be shown to successfully accomplish critical life stages, such as reproduction or overwintering. To confirm overwintering of arthropods in roadsides, sods were cut in late winter in a verge where several years of summer survey data were available. The sods were placed in transparent semi-permeable cages and kept alive during subsequent spring, summer and autumn. All emerging arthropods were caught inside the cages using pitfall and funnel traps and identified to order or family level. Most of the terrestrial arthropod phyla and orders occurring in NW-Europe appeared to be represented. Several groups were further identified to the species level: Carabidae (Coleoptera), Curculionidae (Coleoptera), Araneae, Orthoptera, Apidae (Hymenoptera), Syrphidae (Diptera) and Dephacidae/Cercopidae (Hemiptera). Particularly for the Carabidae, Araneae and Curculionidae, many species recorded in summer were also found to overwinter; species overlap amounted to approximately 67%. Rarefaction of the summer sample or excluding possible summer vagrants, raised this overlap to as much as 88% for the Carabidae. Many of the species successfully overwintering in the roadside verge were generalists, but less common, more stenotopic species were present as well. Not only species hibernating as adults were involved, but also species overwintering in immature stages, indicating reproduction also takes place in the roadside verge. Apparently the roadside occurrence of many arthropod species, including stenotopic and declining ones, is not merely seasonal or incidental, and roadside verges do not necessarily act as a sink only. The ecological importance often attributed to roadside verges should clearly be taken seriously.
Preference of early juveniles of a coral reef fish for distinct lagoonal microhabitats is not related to common measures of structural complexity
Grol, M.G.G. ; Nagelkerken, I. ; Bosch, N. ; Meesters, H.W.G. - \ 2011
Marine Ecology Progress Series 432 (2011). - ISSN 0171-8630 - p. 221 - 233.
seagrass beds - habitat complexity - field experiment - recruitment patterns - nutrient enrichment - mangroves - assemblages - predation - grunts - water
Coral reef populations of a variety of fish and invertebrate species are replenished by individuals that use inshore coastal habitats as temporary juvenile habitats. These habitats vary greatly in their architecture, and different characteristics of structure could play a role in their selection and utilization by resident fauna. To solely investigate the role of structural complexity in microhabitat selection, in situ habitat preference of 48 individuals of the early juvenile stage of a common reef fish (Haemulon flavolineatum) was studied for 4 structurally very different lagoonal microhabitats (i.e. mangrove, seagrass, rubble, coral), using a multiple-choice experiment in field enclosures. This fish species was selected as it utilizes these habitats during different parts of its life cycle. The structural complexity of each microhabitat was changed in each replicate experiment and assessed on the basis of 7 commonly used measures of structure using digitized photographs. We tested the hypothesis that in isolation of other factors, fish prefer the structurally most complex microhabitat that is available, independent of habitat type. However, fish always preferred seagrass and coral microhabitats even when offered at low complexity, and this choice was rather consistent over a 24 h time period. Structural characteristics appeared to be marginally important for the seagrass microhabitat only. Therefore, the differential preference for distinct lagoonal microhabitats does not appear to be driven by measures of structural complexity that are known to be important at the level of individual habitat types. In this light, continuing loss of coral and seagrass habitats in lagoonal environments due to anthropogenic effects is alarming as it affects preferential habitat of certain stages of the life cycle of fishes.
Regional ecotoxicological hazards associated with anthropogenic enrichment of heavy metals
Spijker, J.H. ; Mol, G. ; Posthuma, L. - \ 2011
Environmental Geochemistry and Health 33 (2011)4. - ISSN 0269-4042 - p. 409 - 426.
assemblages - toxicity - account
Regional geochemical data of heavy metals are commonly used for environmental risk assessment and management. Often these data are based on so-called total concentrations, whereas the exposure to the mobile or reactive fraction of these elements finally determines whether the exposed ecosystem is at risk and to which extent. The objective of our research was to develop a wider applicable method for quantitative hazard assessment of soil metal contamination attributable to the activity of man, based on and illustrated with data from the Netherlands. Since chemical availability (0.43 M HNO3 extractable concentrations) of Cd, Cu, Pb and Zn appeared strongly related to the estimated anthropogenic enrichment, we used these concentrations to assess the hazard of human-induced enrichment of these metals. We expressed the enrichment hazard using the toxic pressure concept, which estimates the fraction of biological species (varying between 0 and 1) potentially affected due to the level of exposure to single metals or their local mixtures. This is done using logistic (enrichment) concentration/response models parameterized with ecotoxicological effect data from toxicity tests and mixture models. Hazards varied from very low toxic pressures (lower than 0.01) to (most often) toxic pressure less than 0.05, whereby the latter relates to the so-called 95%-protection criterion used in some soil protection legislations. In rare cases, the toxic pressure exceeded the value of 0.05, to an upper limit of 0.054 for Cd. The rank order of metal enrichment hazards suggests that Cd enrichment induces the largest hazard increase. There are limited (rank order) differences in enrichment hazards between soil types. Comparing the judgement of soils based on soil screening levels and based on toxic pressure of anthropogenic Cd, Cu, Pb and Zn enrichments, the soil screening values appear to more conservative. This exemplifies the use of soil screening values as a method to note regulatory concern, but not always indicating an actual hazard or risk. When screening values are exceeded, refined hazard insights can be obtained, as illustrated in this paper. This provides a more refined insight in the ecotoxic implications of human-induced metal enrichments in soils, as refined basis for risk management decisions.
Taxonomic and functional diversity of farmland bird communities across Europe: effects of biogeography and agricultural intensification
Guerrero, I. ; Morales, M.B. ; Onate, J.J. ; Aavik, T. ; Bengtsson, J. ; Berendse, F. ; Geiger, F. - \ 2011
Biodiversity and Conservation 20 (2011)14. - ISSN 0960-3115 - p. 3663 - 3681.
land-use intensity - species richness - steppe birds - biodiversity - landscape - heterogeneity - productivity - distinctness - assemblages - indicators
Abstract In eight European study sites (in Spain, Ireland, Netherlands, Germany, Poland, Estonia and Sweden), abundance of breeding farmland bird territories was obtained from 500 9 500 m survey plots (30 per area, N = 240) using the mapping method. Two analyses were performed: (I) a Canonical Correspondence Analysis of species abundance in relation to geographical location and variables measuring agricultural intensification at field and farm level to identify significant intensification variables and to estimate the fractions of total variance in bird abundance explained by geography and agricultural intensification; (II) several taxonomic and functional community indices were built and analysed using GLM in relation to the intensification variables found significant in the CCA. The geographical location of study sites alone explains nearly one fifth (19.5%) of total variation in species abundance. The fraction of variance explained by agricultural intensification alone is much smaller (4.3%), although significant. The intersectionexplains nearly two fifths (37.8%) of variance in species abundance. Community indices are negatively affected by correlates of intensification like farm size and yield, whereas correlates of habitat availability and quality have positive effects on taxonomic and functional diversity of assemblages. Most of the purely geographical variation in farmland bird assemblage composition is associated to Mediterranean steppe species, reflecting the bio-geographical singularity of that assemblage and reinforcing the need to preserve this community. Taxonomic and functional diversity of farmland bird communities are negatively affected by agricultural intensification and positively affected by increasing farmland habitat availability and quality.
Evaluation of European diatom trophic indices.
Lototskaya, A.A. ; Verdonschot, P.F.M. ; Coste, M. ; Vijver, B. van de - \ 2011
Ecological Indicators 11 (2011)2. - ISSN 1470-160X - p. 456 - 467.
littoral diatoms - inference models - monitoring eutrophication - water chemistry - benthic diatoms - united-states - rivers - assemblages - bacillariophyceae - streams
Freshwater diatoms are considered to be reliable indicators of the trophic status of rivers and lakes. In the past 30 years, a number of indicator indices have been developed and used for the assessment of trophic conditions all over Europe. It is however still not clear whether the ecologic signature of diatoms differs between these indicator indices. The present study assessed a large number of published European indices on the response of freshwater diatoms to trophic conditions by evaluating the consistency in the use of taxa and their trophic score from seven European indicator indices. The STAR (Standardisations of River Classifications) diatom database, a large set of samples from European running waters, was used to test the application of trophic classifications in water quality assessment. The analysis of taxa in common within the trophic indices showed that there are considerable differences between the indices, for example in the score of trophic values. There was more agreement in classification of taxa within the oligotrophic and the hypertrophic preferences than within the mesotrophic range. Based on these results, a list of diatom taxa, that are consistently used in different trophic indices, was composed. It included 159 ‘reliable’ taxa that are not sensitive to regional setting, water type and taxonomic uncertainty. The list was further accompanied by a description of the taxa's trophic preferences. The large deviation in trophic scores for a number of diatom taxa could most probably be explained by taxonomic uncertainties. Application of these taxa for trophic assessment was questionable. The test set of the 359 STAR samples showed that differences between the trophic indices also lead to a significant variation in the water quality assessment results. Although trophic indices provide an excellent biomonitoring tool, they should be applied with caution, considering the recommendations provided in this paper.
Branched glycerol dialkyl glycerol tetraethers in lake sediments: Can they be used as temperature and pH proxies?
Blaga, C.I. ; Reichart, G.J. ; Schouten, S. ; Lotter, A.F. ; Werne, J.P. ; Kosten, S. ; Mazzeo, N. ; Lacerot, G. ; Damste, J.S.S. - \ 2010
Organic Geochemistry 41 (2010)11. - ISSN 0146-6380 - p. 1225 - 1234.
terrestrial organic-matter - crenarchaeotal membrane-lipids - bit index - water temperatures - reconstruction - transport - palaeothermometer - distributions - assemblages - holocene
A series of surface sediments from 82 lakes of variable water depth and size was analyzed for glycerol dialkyl glycerol tetraethers (GDGTs) in order to investigate the potential of the MBT/CBT (methylation ratio/cyclization ratio of branched tetraethers) as a continental palaeothermometer in lacustrine environments. Branched GDGTs dominated in most sediments, as indicated by the high branched vs. isoprenoid tetraether (BIT) values. We observed that CBT and MBT varied substantially. Mean annual air temperature (MAAT reconstructed) and pH values were calculated using the CBT and MBT values and the calibration from the global soil data set. The MBT/CBT inferred temperatures were considerably lower than measured values. Nevertheless, there was a significant correlation between MAAT reconstructed and MAAT observed on site, although there was still considerable scatter (r(2) 0.47). Lacustrine sediments integrate organic remains of organisms in a lake and its drainage basin, thereby offering a unique opportunity for calibrating MBT and CBT, as small scale variability is averaged out. Since the source of the branched GDGTs in the lake sediments is ambiguous, it is not clear whether only temperature and pH in the catchment area are the driving factors. Therefore, even in lake sediments with high concentrations of branched GDGTs the straightforward application of MBT/CBT as palaeoproxies may be difficult given the uncertainties regarding their source and origin.
Side effects of kaolin particle films on apple orchard bug, beetle and spider communities
Marko, V. ; Bogya, S. ; Kondorosy, E. ; Blommers, L.H.M. - \ 2010
International Journal of Pest Management 56 (2010)3. - ISSN 0967-0874 - p. 189 - 199.
pest-management systems - arthropod - aphid - coccinellidae - insecticide - assemblages - populations - pesticides - coleoptera - hungary
The effects of multiple applications of hydrophobic kaolin particle film on apple orchard bug (Heteroptera), beetle (Coleoptera) and spider (Araneae) assemblages were studied in the Netherlands. Insecticide-free orchard plots served as a control. The kaolin applications significantly reduced the abundance and species richness of the communities and also altered their composition and diversity. The treatments disrupted many non-target groups notably mycophagous, predacious and tourist beetles, zoophagous bugs and spiders. Among spiders, wanderer spiders (Thomisidae, Philodromidae) were most affected, whereas web building spiders (Dictynidae) were least affected. After ceasing the applications in July, the between-treatment differences in composition of all communities and diversity of heteropterans and spiders diminished while the differences in abundance and species richness remained for a long time, until the end of September. Many predator species with good colonisation ability recovered slowly after the treatments, mainly due to the scarcity of prey.
Data integration for European marine biodiversity research: creating a database on benthos and plankton to study large-scale patterns and long-term changes
Vandepitte, L. ; Vanhoorne, B. ; Kraberg, A. ; Craeymeersch, J.A.M. - \ 2010
Hydrobiologia 644 (2010)1. - ISSN 0018-8158 - p. 1 - 13.
taxonomic distinctness - baltic sea - diversity - assemblages - ecology - waters - index - tool
The general aim of setting up a central database on benthos and plankton was to integrate long-, medium- and short-term datasets on marine biodiversity. Such a database makes it possible to analyse species assemblages and their changes on spatial and temporal scales across Europe. Data collation lasted from early 2007 until August 2008, during which 67 datasets were collected covering three divergent habitats (rocky shores, soft bottoms and the pelagic environment). The database contains a total of 4,525 distinct taxa, 17,117 unique sampling locations and over 45,500 collected samples, representing almost 542,000 distribution records. The database geographically covers the North Sea (221,452 distribution records), the North-East Atlantic (98,796 distribution records) and furthermore the Baltic Sea, the Arctic and the Mediterranean. Data from 1858 to 2008 are presented in the database, with the longest time-series from the Baltic Sea soft bottom benthos. Each delivered dataset was subjected to certain quality control procedures, especially on the level of taxonomy. The standardisation procedure enables pan-European analyses without the hazard of taxonomic artefacts resulting from different determination skills. A case study on rocky shore and pelagic data in different geographical regions shows a general overestimation of biodiversity when making use of data before quality control compared to the same estimations after quality control. These results prove that the contribution of a misspelled name or the use of an obsolete synonym is comparable to the introduction of a rare species, having adverse effects on further diversity calculations. The quality checked data source is now ready to test geographical and temporal hypotheses on a large scale